Back-flushable filter having valved flusing pathway

ABSTRACT

A filter operable in either a filtering mode or in a flushing mode, includes a cylindrical filter body, and a plurality of partitions defining a plurality of axially-extending, circumferentially-spaced filter compartments each communicating with an axial section of the filter body. All the filter compartments communicate with the fluid inlet except for at least one filter compartment which is blocked. A flushing pathway is provided between each blocked compartment and the flushing outlet. A valve in the flushing pathway is movable either to (a) a closed position during the normal filtering mode, or (b) an open position during the flushing mode.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to filters and particularly toback-flushable filters which can be cleaned by back-flushing through thefilter body.

Many filter constructions are known which permit the filter to becleaned by back-flushing through the filter body. Generally, suchfilters are operable either in a normal filtering mode wherein theyperform their normal filtering functions of removing solid particlesfrom a fluid (e.g., water) circulated through the filter, or in aflushing mode wherein they clean the filter by back-flushing the filterbody. Examples of such filter constructions are described in my priorU.S. Pat. Nos. 4,632,757 and 4,806,217.

OBJECTS AND BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide a filter which can beefficiently operated in either the normal filtering mode, or in aflushing mode wherein only one section, or a few sections, of the filterbody are cleaned at any given instant by back-flushing, all the sectionsbeing sequentially cleanable in this manner, while the sections notbeing flushed at any given instant perform their normal filteringfunction. Another object of the invention is to provide a filter of theforegoing type made of relatively few simple parts which can be producedand assembled in volume and at low cost.

According to the present invention, there is provided a filter operablein either a filtering mode or in a flushing mode, comprising: a housingincluding a cylindrical filter chamber, and further including a fluidinlet, a fluid outlet, and a flushing outlet communicating with thefilter chamber; a cylindrical filter body disposed within the filterchamber and having an upstream face communicating with the fluid inletand a downstream face communicating with the fluid outlet; and aplurality of partitions defining, with the housing and upstream face ofthe filter body, a plurality of axially-extending,circumferentially-spaced filter compartments each communicating with anaxial section of the filter body. The filter further includes blockingmeans blocking communication between the fluid inlet and the at leastone filter compartment, while unblocking the remaining filtercompartments by permitting communication between them and the fluidinlet; and a flushing pathway between the blocked filter compartment andthe flushing outlet. A valve in the flushing pathway is movable either:(a) to a closed position during the normal filtering mode, wherein afiltering operation is performed by all the axial sections of the filterbody communicating with the unblocked filter compartments to filter thefluid flowing from the fluid inlet to the fluid outlet, or (b) to anopen position during the flushing mode, wherein the same filteringoperation is performed by all the axial sections of the filter bodycommunicating with the unblocked filter compartments, and a flushingoperation is performed to flush, via the flushing outlet, each sectionof the filter body communicating with a blocked filter compartment. Theblocking means is rotatable with respect to the filter body to enablethe blocking means to be aligned with, and thereby to perform a flushingoperation with respect to, all the axial sections of the filter body.

As will be described more particularly below, a valve constructed inaccordance with the foregoing features may be efficiently operatedaccording to a normal filtering mode, or according to a flushing mode inwhich the various sections of the filter body are sequentially flushedwhile the sections not being flushed at any particular instant continueto perform their normal filtering functions. In addition, such filtersmay be constructed of a few, relatively simple part which can beproduced in volume and at low cost.

Several embodiments of the invention are described below for purposes ofexample.

According to one described embodiment, the filter body is fixed, and theblocking member is rotatable with respect to the filter body. Inaddition, the valve includes a valve stem for moving the valve to eitherits open or closed position. The valve stem is coupled to a handlemanually movable externally of the housing and is also coupled to theblocking member within the housing for rotating it with respect to thefilter body.

According to a second described embodiment, the housing includes aninner tubular section formed with the fluid inlet at one end and withthe fluid outlet at the opposite end, and an outer cylindrical sectionformed with the flushing outlet. The outer cylindrical section ismovable axially with respect to the inner tubular section to operate thevalve, and is also movable angularly with respect to the inner tubularsection to rotate the blocking member with respect to the filter body.In this embodiment, the valve includes an annular seal received betweenthe inner tubular section and the outer cylindrical section in theclosed position of the valve, the annular seal being fixed to one of thesections such that it is spaced from the other section when the outercylindrical section is moved axially to the open position of the valve.

Further features and advantages of the invention will be apparent fromthe description below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, withreference to the accompanying drawings, wherein:

Fig. 1 is a longitudinal sectional view illustrating one form of filterconstructed in accordance with the present invention, the filter beingshown in its normal filtering mode of operation;

FIGS. 2, 3, 4 and 5 are sectional views along lines II--II, III--III,IV--IV and V--V of FIG. 1 respectively;

FIG. 6 is a view similar to that of Fig. 1 but showing the filter in itsflushing mode of operation;

FIG. 7 is a longitudinal sectional view illustrating a second form offilter constructed in accordance with the present invention, the filterbeing shown in its normal filtering mode;

FIG. 8 is a sectional view along lines VIII--VIII of FIG. 7;

FIG. 9 is a perspective view of a sleeve included in the filter of FIG.7;

FIG. 10 is a perspective view illustrating the blocking member includedin the filter of FIG. 7;

FIG. 11 is a view similar to that of FIG. 7 but illustrating the filterin its flushing mode of operation;

FIG. 12 is a longitudinal sectional view illustrating a further form offilter constructed in accordance with the present invention, the filterbeing shown in its normal filtering mode of operation;

FIGS. 13, 14 and 15 are sectional views along lines XIII--XIII, XIV--XIVand XV--XV of FIG. 12, respectively;

FIG. 16 is a view similar to that of FIG. 12 but showing the filter inits flushing mode of operation;

and FIG. 17 is a longitudinal sectional view illustrating a further formof filter constructed in accordance with the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS The Filter of FIGS. 1-6

The filter illustrated in FIGS. 1-6 is particularly useful for filteringwater, but may also be used for filtering other fluids such as otherliquids, air, or other gasses. The filter includes a housing 2 formedwith an inlet 3 for the water (or other fluids) to be filtered, anoutlet 4 for the water after it has been filtered, and a flushing outlet5 for flushing out of the housing, during a flushing mode of operation,the dirt removed from the water during the normal filtering operation.

Inlet 3 communicates, via an axial passage 6, with a cylindrical filterchamber 7 within housing 2. A cylindrical filter body 8 is disposedwithin filter chamber 7. The outer surface 8a of the filter body 8communicates with the fluid inlet 3 via axial passageway 6 and thusconstitutes the upstream face of the filter body; whereas the innersurface 8b of the cylindrical body communicates with the fluid outlet 4via an annular passageway 9 between the filter body and the axialpassageway 6.

The cylindrical filter body 8 is constituted of a stack of filter discshaving contacting faces formed with ribs to define filtering passagewaysbetween each pair of discs. As one example, the filter body 8 may beconstructed as described in my prior U.S. Pat. No. 4,661,250. It will beappreciated, however, that other filter body constructions may be used,e.g., cylindrical screens.

The inner surface of housing 2 is formed with a plurality ofaxially-extending, circumferentially-spaced ribs 10 which aredimensioned so that their tips engage the outer surface of thecylindrical filter body 8. As shown in FIGS. 2-4, ribs 10 serve aspartitions cooperable with the outer surface of the cylindrical filterbody 8 to define a plurality of axially-extending,circumferentially-spaced filter compartments 11 each communicating witha corresponding axially-extending portion or section of the filter body8. In the example illustrated, there are twelve ribs defining twelvefilter compartments 11.

The illustrated filter further includes a blocking member, generallydesignated 12, which blocks communication between the fluid inlet 3 andat least one of the filter compartments 11, while permittingcommunication between the fluid inlet and the remaining filtercompartments. In the example illustrated in FIGS. 1-6, blocking member12 includes a circular disc 13 of the same diameter as the cylindricalfilter body 8, and is formed with two rectangular-shaped blockingelements 14 on opposite sides of the center point 13a of the disc. Eachblocking element 14 is in the configuration of a U-shaped wall having amiddle wall 14a, two parallel end walls 14b, 14c (FIG. 3) spaced apartthe distance between a pair of the ribs 10 and aligned with those ribs,and a bottom wall 14d (FIG. 1). Each blocking element 14 thus blocks thefilter compartment 11 defined by the two ribs 10 with which the blockingelement is aligned, and has an open side facing the filter compartmentblocked thereby.

It will thus be seen that in the arrangement illustrated particularly inFIGS. 2-4, in any one position of the blocking member 12, its twoblocking elements 14 block the two filter compartments 11 on oppositesides of the filter, while unblocking the remaining ten filtercompartments.

Housing 2 includes a wall 15 (FIGS. 1, 6) which separates the filterchamber 7 from the flushing outlet 5. Wall 15 is formed with a centralopening 16 closable by a valve 17. Valve 17 is carried at one end of astem 18; the opposite end of stem 18 passes through an opening in theend wall 19 of housing 2 and is connected to a handle 20 externally ofthe housing. Valve 17 also carries a pair of pins 21 passing throughopenings formed on opposite sides of the center 13a of the blockingmember disc 13. A spring 22 urges handle 20 outwardly of housing 2, andvalve 17 to its closed position with respect to opening 16.

The filter illustrated in FIGS. 1-6 may be used in the following manner:

Normally, spring 22 and the water pressure urge handle 20 outwardly ofhousing 2, and the valve 17 to its closed position with respect toopening 16, as illustrated in FIG. 1. In this valve-closed position,valve 17 blocks communication between the filter chamber 7 and theflushing outlet 5. In addition, the open end of each of the two blockingelements 14 of the blocking member 12 is aligned with one of the filtercompartments 11.

When the filter is in this condition, it will perform a normal filteringoperation with respect to the ten axial sections of the filter body 8aligned with the ten ublocked filter compartments 11. Thus, in thenormal filtering mode, the water introduced via inlet 3 flows throughthe axial passage 6, under disc 13 of the blocking member 12 to all thefilter compartments 11 except the two blocked by the blocking elements14 of blocking member 12, to the upstream (outer) surface 8a of all theaxial sections of the filter body 8 exposed to the unblocked filtercompartments 11, through the filter discs of the filter body 8 to thedownstream (inner) side of the filter body, and out via passageway 9 tothe outlet 4.

During this operation, communicating between the flushing outlet 5 andthe two filtering compartments 11 blocked by the two blocking elements14 is blocked by the closed valve 17 so that no flushing action isperformed at this time.

To have the filter perform a flushing action in a flushing mode ofoperation, handle 20 is grasped and pushed inwardly, to move valve 17 toits open position with respect to opening 16, as shown in FIG. 6. Thisconnects the interior of blocking elements 14 of blocking member 12 tothe flushing outlet 5. In this condition of the filter, the higherpressure of the water at the downstream (inner) side 8b of the filterbody 8 produces a reverse flow, as shown by the arrows in FIG. 6,through the two filter compartments 11 with which blocking elements 14are aligned, and through the flushing outlet 5. The dirt accumulated onthe upstream (outer) surface 8a of the two sections of the filter body 8aligned with the two unblocked filter compartments 11 is thus flushedout through the flushing outlet 5. However, the normal filteringoperation still continues with respect to the other ten filter sectionsaligned with the unblocked filter compartments 11, so that the filtercontinues to operate to perform its normal filtering function withrespect to these sections of the filter body 8.

Handle 20 is then turned to rotate blocking member 12 in order to alignits two blocking elements 14 successively with all the filtercompartments 11, to thereby sequentially flush out the dirt particlesaccumulated on the upstream (outer) surface 8a of all the sections ofthe filter body.

It will thus be seen that the filter illustrated in FIGS. 1-6 may beoperated according to a normal filtering mode by moving valve 17 to itsclosed position as illustrated in FIG. 1, or according to a flushingmode by moving the valve to its open position as illustrated in FIG. 6,and then rotating handle 20 to rotate the blocking member 12 tosuccessively flush all the sections of the filter body 8 out through theflushing outlet 5.

The Filter of FIGS. 7-11

The filter illustrated in FIGS. 7-11 operates basically in the samemanner as that of FIGS. 1-6 but is of a substantially differentconstruction.

Thus, the filter illustrated in FIGS. 7-11 includes a housing, generallydesignated 30, constituted of an inner tubular section 31 and an outercylindrical section 32 movable both axially and angularly with respectto section 31. The central tubular section 31 is formed at one end witha fluid inlet 33, and at the opposite end with a fluid outlet 34;whereas the outer cylindrical section 32 is formed with the flushingoutlet 35. Direct communication between the fluid inlet 33 and the fluidoutlet 34 is blocked by a circular partition disc 36 secured within theinner tubular section 31.

The space between the two housing sections 31 and 32 defines acylindrical filter chamber 37 receiving a cylindrical filter body 38. Asin the construction of FIGS. 1-6, the filtering body 38 may also be inthe form of a stack of grooved filter discs.

The inner tubular section 31 of housing 30 is formed with a firstannular array of inlet openings 39 on one side of partition 36 toestablish communication between the inlet 33 and the outer surface 38aof filter body 38, so that surface 38a of the filter body 38 constitutesits upstream face. Inner tubular section 31 is formed with an annulararray of outlet openings 40 on the opposite side of partition disc 36 toestablish communication between the inner surface 38b of the filter body38 and the fluid outlet 34, so that surface 38b of the filter bodyconstitutes its downstream face.

The outer cylindrical section 32 of housing 30 is formed with aplurality of axially-extending, circumferentially-spaced ribs 41 (FIG.8) defining, with the outer surface of the filter body 38, a pluralityof filter compartments 42. In the example illustrated in FIG. 8, thereare eight such filter compartments, each exposed to an axial section ofthe filter body 38. A sleeve 43 (FIG. 9) is fixed to the outercylindrical section 32 of the housing and is formed with an opening 44for each of the filter compartments 42. The inner tubular section 31 ofthe housing is formed with one inlet opening 39 for each of the filtercompartments 42.

A blocking member 45 (FIG. 10), including an annular disc 46 and asingle blocking element 47, is fixed to housing section 31 by aplurality of pins 48 securing disc 46 to an annular seal 49, which inturn is fixed to housing section 31 by pins 49a. As shown particularlyin FIG. 10, blocking element 47 is of substantially U-configuration. Itincludes a curved middle wall 47a conforming to the curvature of theinner housing section 31 and of a length to close one of its inletopenings 39. Blocking element 47 further includes a pair of parallelside walls 47b, 47c spaced apart a distance equal to the spacing betweenribs 41 in the outer housing section 32 such that the interior of theblocking member communicates with one of the filter compartments 42defined by ribs 41.

Annular seal 49 is fixed by pins 49a to the outer surface of the innerhousing section 31 adjacent its inlet end 33. In the normal position ofthe outer housing section 32 illustrated in FIG. 7, seal 48 is receivedbetween housing section 31 and a reduced-diameter end 32a of housingsection 32. It thereby serves as a valve which blocks communicationbetween the interior of blocking element 47 and the flushing outlet 35during the normal filtering mode of operation of the filter. However,when the outer housing section 32 is moved axially (rightwardly in FIG.7) to the position illustrated in FIG. 11, the reduced-diameter end 32aof housing section 32 moves away from the annular seal 49 to therebyopen the valve defined by the seal and to establish communicationbetween the interior of blocking element 47 and the flushing outlet 35.

The inner tubular section 31 further includes a stop 50 to limit theaxial position of the outer tubular section 32.

The filter illustrated in FIGS. 7-11 operates as follows:

In the normal filtering mode of operation, the outer housing section 32is in the position shown in FIG. 7, against stop 50. In this conditionof the filter, the valve defined by the annular seal 49 fixed to theinner housing section 31 is closed, i.e., engaging the reduced-diameterend 32a of housing section 32, thereby blocking communication betweenthe interior of blocking element 47 and the flushing outlet 35.

The filter thus operates in a normal filtering mode, in which the waterinletted via inlet 33 passes via all the openings 39, except the oneblocked by blocking element 47, through openings 44 of sleeve 43 intothe filter compartments 42 defined by the ribs 41, and through therespective axial sections of the filter body 38, the outlet openings 40,and out through the outlet 34. All the sections of the filter body 38are thus effective to filter the water, except for the section facingthe filter compartment 42 blocked by the blocking member 47.

When it is desired to clean the filter body 38, the outer housingsection 32 is manually grasped and moved rightwardly away from stop 50to the position illustrated in FIG. 11. In this position of housingsection 32, its end 32a moves away from the annular seal 49, to therebyopen the valve defined by the seal and to establish communicationbetween the interior of blocking element 47 and the flushing outlet 35.The pressurized water at the downstream face of the axial section of thefilter body 38 facing the filter compartment 42 blocked by the blockingelement 47 is now connected to the atmosphere via the flushing outlet35. That section of the filter body is therefore flushed of any dirtparticles on its upstream (outer) surface. The remainder of the filterbody, however, continues to perform a normal filtering function.

The outer housing section 32 may then be manually rotated in order tosequentially align the interior of blocking element 47 with all theother filter compartments 42 through opening 44 of sleeve 43 to therebyflush the other sections of the filter body 38 out through the flushingoutlet 35.

The Filter of FIGS. 12-16

The filter illustrated in FIGS. 12-16 includes a housing, generallydesignated 60, constituted of an inner tubular section 61 and an outercylindrical section 62 movable only angularly (rotatably) with respectto the inner housing section 61. The inner housing section 61 is formedwith a fluid inlet 63 at one end, a fluid outlet 64 at the opposite end,and a flushing outlet 65 at the same end as the fluid inlet 63. Directcommunication between the fluid inlet 63 and fluid outlet 64 is blockedby a partition disc 66 within the inner housing section 61.

The space between the two housing sections 61 and 62 defines acylindrical filter chamber 67 receiving a cylindrical filter body 68,e.g., a stack of grooved filter discs. An annular array of inletopenings 69 on one side of partition disc 66 establish communicationbetween the inlet 63 and the outer surface 68a of filter body 68. Anannular array of outlet openings 70 on the opposite side of partitiondisc 66 establish communication between the inner surface 68b of thefilter body and the fluid outlet 64.

The outer housing section 62 is formed with a plurality ofaxially-extending, circumferentially-spaced ribs 71 defining a pluralityof filter compartments 72 with the outer surface of filter body 68.Filter compartments 72 communicate with the inlet openings 69 via aradial vane assembly, generally designated 73, including a pair of enddiscs 73a, 73b, securing a plurality of radial vanes 73c between them.The vane assembly 73 and the filter body 68 are both secured within theouter housing section 62 so as to rotate with that section with respectto the inner housing section 61.

A blocking member, generally designated 75, is fixed within the innerhousing section 61 between the fluid inlet 63 and the circular partitiondisc 66 so as to block at least one of the fluid inlet openings 69 fromthe fluid inlet 63. Blocking member 75 includes two radially-extendingwalls 75a, 75b joined together at their inner ends in alignment with thelongitudinal axis of housing sections 61, and joined at their outer endsto housing section 61 so as to define a sector of a cylinder closed atone end by the circular partition disc 66, and closed at the oppositeend by a circular disc sector 75c.

In the example illustrated in FIGS. 12-16, the ribs 71 define eightfilter compartments 72; housing section 61 is formed with six inletopenings 69; and blocking member 75 defines a 90° sector of a cylinder.

The flushing outlet 65 communicates with the interior of blocking member75 by means of a flushing opening 76 formed in housing section 61, and amanually-operated on/off valve 77.

The filter illustrated in FIGS. 12-16 operates as follows:

In the normal filtering mode of operation, shutoff valve 77 is in itsclosed position as illustrated in FIG. 12, thereby blockingcommunication between the flushing outlet 65 and the interior ofblocking member 75. The filter thus operates in a filtering mode, inwhich the water inletted via inlet 63 passes through all the openings 69into the filter chamber 67, except the opening located within theinterior of the blocking member 75. All the sections 72 of the filterbody 68 are thus effective to filter the water exiting via outletopening 70 and outlet 64, except the inlet opening 69 located withinblocking member 75.

When it is desired to clean the filter body 68, valve 77 is manuallyopened, thereby establishing communication between the interior ofblocking member 75 and the flushing outlet 65. The pressurized water atthe upstream (outer) face of filter body 68 facing the blocked inletopening 69 is now connected to the atmosphere via the flushing outlet65. That section of the filter body is therefore flushed of any dirtparticles on its upstream (outer) surface, while the remaining sectionsof the filter body 68 continue to perform their normal filteringfunction.

The outer housing section 62 may then be manually rotated in order tosequentially align the radial vane assembly 73 with inlet opening 69 nowconnected to the atmosphere via blocking member 75, open valve 77, andflushing outlet 65. As each of the compartments 72 of the filter isbrought into communication, via vane assembly 73, with opening 69communicating with the atmosphere, the respective axial section of thefilter 68 is similarly flushed of any dirt particles on its upstream(outer) surface.

The Filter of FIG. 17

FIG. 17 illustrates a filter for attachment to a fluid line in anoff-axis manner, i.e., with the longitudinal axis of the filter notin-line with the fluid line as in the embodiment of FIGS. 12-16. Thefilter of FIG. 17 thus also includes a housing, generally designated 80,constituted of an inner tubular section 81 and an outer cylindricalsection 82. In this case, however, the outer housing section 82 isattached to the fluid line and therefore is fixed, whereas the innerhousing section 81 is rotatable with respect to the outer housingsection 82. Thus, the outer housing section 82 is formed with the fluidinlet 83 and with the fluid outlet 84, whereas the inner housing sectionis formed with the flushing outlet 85.

In the filter construction illustrated in FIG. 17, the fluid inlet 83 isseparated from the fluid outlet 84 by a partition including an annularring 86 and a separator tube 87 fixed at its inner end to annular ring86 and extending axially of the inner housing section 81 to the fluidoutlet 84. Separator tube 87 is coaxial with, but of smaller diameterthan, the inner housing section 81 to define an annular inlet passageway87a between it and housing section 81, and an outlet passageway 87bleading to the fluid outlet 84.

The space between the two housing sections 81 and 82 defines the filterchamber containing a cylindrical filter body 88, e.g., a stack of ribbeddiscs. The inner housing section 81 is formed with an annular array ofinlet openings 89 on one side of partition ring 86 to communicate withthe inlet passageway 87a, and with an annular array of outlet openings90 on the opposite side of partition ring 86 to communicate with theoutlet passageway 87b.

The inner surface of the outer housing section 82 is formed with aplurality of axially-extending ribs 91 defining a plurality of filtercompartments 92 with the outer surface of the filter body 88, as in thefilter of FIGS. 12-16. There is at least one inlet opening 89 in theinner housing section 82 for each of the filter compartments 92, exceptfor one compartment which is to be blocked during the filter mode ofoperation and which is therefore devoid of an inlet opening 89. Theportion of the inner housing section 82 devoid of an inlet opening 89thus serves as blocking means blocking communication between the inletand one of the filter compartments 92 during the filter mode ofoperation.

A radial vane assembly 93, of the same construction as assembly 73 inFIGS. 12-16, is provided at one end of the filter body 88. In this case,however, a second vane assembly 94 of the same construction is providedat the opposite end of the filter body.

A disc 95 is fixed within the inner housing section 81 between the fluidoutlet openings 90 and the flushing outlet 85. That end of housingsection 81 is formed with a flushing opening 96 radially aligned withradial vane assembly 94, and axially aligned with the portion of theinner housing section 82 devoid of an inlet opening 89. A manuallycontrolled on/off valve 97 is provided at the end of housing section 81to control the flushing outlet 85.

The filter illustrated in FIG. 17 operates as follows:

During the normal filtering mode of operation, valve 97 is in its closedcondition as illustrated in FIG. 17. In this condition, the flushingoutlet 85 is closed, so that the filter operates according to a normalfiltering mode. Thus, the fluid inletted at 83 flows through the annularinlet passageway 87a and the inlet openings 89 to the outer (upstream)surface of all the filter compartments 92 except the one blocked by thelack of an inlet opening 89 in the inner housing section 89. The waterthen flows through the filter body 88 of the unblocked compartments 92,through the outlet openings 90, through the outlet passageway 87b, andout through outlet 84. All the axial sections of the filter body 88aligned with the unblocked compartments 92 will therefore perform anormal filtering function.

When it is desired to clean the filter, valve 97 is opened, therebyestablishing communication between the atmosphere and the blocked filtercompartment 92 with which the flushing opening 96 is aligned.Accordingly, that axial section of the filter body 88 will beback-flushed via the flushing outlet 85. The inner housing section 81 ofthe filter may then be manually rotated in order to bring the flushingopening 96 successively into alignment with all the other axial sectionsof the filter body 88 to flush them out in succession.

While the invention has been described with respect to several preferredembodiments, it will be appreciated that these are set forth merely forpurposes of example, and that many variations may be made. For example,the invention could be included in automatically-operated filters havingsensors for sensing the differential pressure between the upstream anddownstream sides of the filter body and, in response thereto,automatically open the valve to produce a flushing operation, and/oralso automatically rotate the blocking member to sequentially flush allthe sections of the filter body. Many other variations, modificationsand applications of the invention will be apparent.

I claim:
 1. A filter operable in either a filtering mode or in aflushing mode, comprising:a housing including a cylindrical filterchamber, and further including a fluid inlet, a fluid outlet, and aflushing outlet communicating with said filter chamber; a cylindricalfilter body disposed within said filter chamber and having an upstreamface communicating with said fluid inlet and a downstream facecommunicating with said fluid outlet; a plurality of partitionsdefining, with the housing and upstream face of the filter body, aplurality of axially-extending, circumferentially-spaced filtercompartments each communicating with an axially-extending section of thefilter body; blocking means for blocking communication between saidfluid inlet and at least one filter compartment, while unblocking eachremaining filter compartment by permitting communication with said fluidinlet; a flushing pathway between each blocked filter compartment andsaid flushing outlet; and a valve in said flushing pathway movableeither: (a) to a closed position during the normal filtering mode,wherein a filtering operation is performed in each unblocked filtercompartment to filter the fluid flowing from the fluid inlet to thefluid outlet, or (b) to an open position during the flushing mode,wherein the same filtering operation is performed in each unblockedfilter compartment, and a flushing operation is performed to flush, viathe flushing outlet, in each blocked filter compartment; said blockingmeans and filter body being rotatable relative to each other to enablesaid blocking means to be aligned with, and thereby to perform aflushing operation with respect to, all the axially-extending sectionsof the filter body.
 2. The filter according to claim 1, wherein saidpartitions are constituted of a plurality of axially-extendingcircumferentially-spaced ribs formed on the inner surface of thehousing.
 3. The filter according to claim 1, wherein said filter body isfixed, and said blocking means includes a blocking member rotatable withrespect to said filter body.
 4. The filter according to claim 3, whereinsaid valve includes a valve stem for moving the valve to either its openposition or closed position.
 5. The filter according to claim 4, whereinsaid valve stem is also coupled to said blocking member for rotating itwith respect to the filter body.
 6. The filter according to claim 4,wherein said valve stem passes through said housing and is coupled to ahandle manually movable from externally of the housing.
 7. A filteroperable in either a filtering mode or in a flushing mode, comprising;ahousing including a cylindrical filter chamber, and further including afluid inlet, a fluid outlet, and a flushing outlet communicating withsaid filter chamber; a cylindrical filter body disposed within saidfilter chamber and having an upstream face communicating with said fluidinlet and a downstream face communicating with said fluid outlet; aplurality of partitions defining, with the housing and upstream face ofthe filter body, a plurality of axially-extending,circumferentially-spaced filter compartments each communicating with anaxially-extending section of filter body; blocking means for blockingcommunication between said fluid inlet and at least one filtercompartment, while unblocking each remaining filter compartment bypermitting communication with said fluid inlet; a flushing pathwaybetween each blocked filter compartment and said flushing outlet; and avalve in said flushing pathway movable either: (a) to a closed positionduring the normal filtering mode, wherein a filtering operation isperformed in each unblocked filter compartment to filter the fluidflowing from the fluid inlet to the fluid outlet, or (b) to an openposition during the flushing mode, wherein the same filtering operationis performed in each unblocked filter compartment, and a flushingoperation is performed to flush, via the flushing outlet, in eachblocked filter compartment; said blocking means and filter body beingrotatable relative to each other to enable said blocking means to bealigned with, and thereby to perform a flushing operation with respectto, all the axially-extending Sections of the filter body; said blockingmeans including a blocking element for each filter compartment blockedby the blocking means; each of said blocking elements including a cavityfacing the filter compartment blocked thereby, which cavity communicateswith the flushing outlet via said valve.
 8. The filter according toclaim 7, wherein each said blocking element is in the configuration of aU-shaped wall having an open side facing the filter compartment blockedthereby.
 9. The filter according to claim 7, wherein said blocking meansincludes a blocking member having two blocking elements on oppositesides of the axis of the blocking member.
 10. A filter operable ineither a filtering mode or in a flushing mode, comprising:a housingincluding a cylindrical filter chamber, and further including a fluidinlet, a fluid outlet; and a flushing outlet communicating with saidfilter chamber; a cylindrical filter body disposed within said filterchamber and having an upstream face communicating with said fluid inletand a downstream face communicating with said fluid outlet; a pluralityof partitions defining, with the housing and upstream face of the filterbody, a plurality of axially-extending, circumferentially-spaced filtercompartments each communicating with an axially-extending section of thefilter body; blocking means for blocking communication between saidfluid inlet and at least one filter compartment, while unblocking eachremaining filter compartment by permitting communication with said fluidinlet; a flushing pathway between each blocked filter compartment andsaid flushing outlet; and a valve in said flushing pathway movableeither: (a) to a closed position during the normal filtering mode,wherein a filtering operation is performed in each unblocked filtercompartment to filter the fluid flowing from the fluid inlet to thefluid outlet, or (b) to an open position during the flushing mode,wherein the same filtering operation is performed in each unblockedfilter compartment, and a flushing operation is performed to flush, viathe flushing outlet, in each blocked filter compartment; said blockingmeans and filter body being rotatable relative to each other to enablesaid blocking means to be aligned with, and thereby to perform aflushing operation with respect to, all the axially-extending sectionsof the filter body; said housing including an inner tubular section, anouter cylindrical section defining said cylindrical filter chamberbetween it and the inner tubular sections, and a partition in said innertubular section; said inner tubular section being formed with an annulararray of inlet openings therethrough on one side of said latterpartition, and with an annular array of outlet openings therethrough onthe opposite side of said latter partition.
 11. The filter according toclaim 10, wherein said outer cylindrical section is movable axially withrespect to said inner tubular section to operate said valve, and is alsorotatable around said inner tubular section to rotate said blockingmeans with respect to said filter body.
 12. The filter according toclaim 10, wherein said valve includes an annular seal received betweenthe inner tubular section and the outer cylindrical section in theclosed position of the valve, said annular seal being fixed to one ofsaid latter two sections such that it becomes spaced from the othersection when the outer cylindrical section is moved axially with respectto the inner tubular section to the open position of the valve.
 13. Thefilter according to claim 10, wherein said outer cylindrical section andsaid cylindrical filter body are rotatable with respect to said innertubular section.
 14. The filter according to claim 13, wherein saidfluid inlet and said fluid outlet are formed at the opposite ends ofsaid inner tubular section of the housing, and said flushing outlet isformed in said outer cylindrical section of the housing.
 15. The filteraccording to claim 14, wherein said blocking means comprises a blockingmember secured to said inner tubular section of the housing to block oneof said inlet openings therethrough.
 16. The filter according to claim10, wherein said outer housing section further includes a radial vaneassembly enclosing said annular array of inlet openings and rotatablewith said filter body to direct the inletted fluid to an annular regionbetween the outer housing section and the filter body.
 17. The filteraccording to claim 10, wherein said outer cylindrical section of thehousing is formed with said fluid inlet and said fluid outlet, and saidinner tubular section of the housing is formed with said flushing outletand is rotatable with respect to said outer cylindrical section and thecylindrical filter body therein.
 18. The filter according to claim 17,wherein said inner tubular section of the housing is formed with a saidinlet opening for each of said filter compartments but is devoid of aninlet opening for the at least one compartment to be blocked from thefluid inlet; said flushing outlet being formed in said inner tubularsection so as to not be in axial alignment with an inlet opening. 19.The filter according to claim 18, wherein said outer housing sectionincludes a radial vane assembly enclosing said annular array of inletopenings to direct the inletted fluid to an annular region between theouter housing section and the filter body.
 20. The filter according toclaim 19, wherein said outer housing section further includes a secondradial vane assembly enclosing the end of said inner housing sectionformed with said flushing opening and effective upon rotation of saidinner housing section to connect said axial sections of the filter bodysequentially to the flushing outlet.